Being inane, Virginia lacks ability (6)
I believe the answer is:
vacant
'being inane' is the definition.
(thesaurus)
'virginia lacks ability' is the wordplay.
'virginia' becomes 'va' (US state abbreviation).
'lacks ability' becomes 'cant' (I've seen this before).
'va'+'cant'='VACANT'
(Other definitions for vacant that I've seen before include "Not occupied, perhaps apartment" , "Horse in a race" , "as gents often are!" , "... Blank" , "Unoccupied - unthinking" .)